In a previous post here at SMR we have covered the outcomes of static and dynamic stretching on performance tasks and how they are affected. Traditionally we have been taught to perform static stretches to increasing ROM and reduce injury before activity. However, what if static stretching has a negative impact on performance? Simic et al. conducted a meta-analytical study to quantitatively combine the results of previous individual static stretch-related articles and estimate the acute effects on muscle strength (peak force, torque or 1 rep max either isokinetic or isometric), power, and explosive muscular performance [categorized as rate of force development, jump, sprint and throwing performance]. They took their analysis one step further by trying to determine if the acute effects were specific to A) subject attributes (age, gender and training status [athlete versus non-athlete]) B) performance tests utilized and C) the time duration of the applied static stretch (SS). For this study, a literature search was conducted across multiple online databases focusing on published journal articles that reported on healthy human subjects, SS effects on muscular power, strength and explosiveness, SS lasting < 30 min and written in English. The authors were able to find 104 articles that met their criteria, from which they were able to extract data and statistically standardize. After data analysis the authors were able to determine significant decreases in muscular strength (-5.4%), and explosive muscular performance (-2.0%) after acute bouts of SS, but the decrease in muscle power (-1.9%) was not deemed statistically significant. In regards to muscle strength, there was a significant difference when comparing the strength reduction of the isometric and isokinetic tasks, with isometric tests experiencing a greater decrease in strength than isokinetic tests(-6.5% vs. -3.9%). The decrease in muscle strength and explosive muscular performance was found to be irrespective of subject age, gender and training status. While the decrease in muscle power didn't reach significance, the authors believe that this is an area that should be focused on during future research based upon the limited amount of data available. The authors also noticed a significant reduction in the negative effects on explosive muscular performance as the duration of SS stays under 45 seconds.

Is there still a place for static stretch in pre-exercise warm-up based upon these results? One item to note is the length of the static stretch. Simic was able to find a decreased negative effect when stretching was kept under 45 sec/muscle group. Many times the individual will stretch a specific area for much shorter than that time period, often times to a 10-count. So in truth, to what extent are we seeing negative effects on performance? With the reductions in muscular strength, power and explosive muscle performance the authors state these results can be applied to both young and old populations, males and females, as well as athletes versus non-athletes. If their analysis is accurate, then these findings can conceivably be instituted for all active individuals. Furthermore, they go on to state these findings “strongly suggest that the usage of SS as the sole activity during warm-up routine should generally be avoided.” However, most structured warm-ups that higher level athletes engage in today are not centered around static stretching There is a balance between both SS and dynamic stretching prior to activity, but should we now begin to think about restructuring not only our warm-up sessions but also warm (cool)-down components, as well? Removing the SS portion of the warm-up can conceivably minimize or eliminate the negative effects that SS will have on these studied performance elements, while focusing on SS during warm-down may allow the individual to still gain ROM and prevent injury before going into the next session. What are your thoughts? How do you structure the warm-up and cool-down elements of your athletes’ activities? If your athletes aren't engaging in any form of structured cool-down, do you believe, based upon these findings that they should begin to do so?

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Anonymous
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Can you please provide information as to what research has been done on growing children/adolescents? Also - has research been done on warm up activities that perform static stretching followed by dynamic stretching (thus decreasing the physiologic negative effects on performance that static stretching alone creates)?

Are you interested in the influence of static stretching on performance measures in children or an outcome other than performance?

A lot of the studies I have seen comparing dynamic and static stretches have been just that. I'm not sure how many studies have explored the influence of static stretching with dynamic stretching but based on the data I'm not sure this would change the fact that static stretches seem to influence performance measures; particularly when longer stretches are performed. I recommend seeing a previous post regarding a systematic review by Kay et al that highlighted the relevance of duration of stretch (http://sportsmedresearch.blogspot.com/2011/07/effect-of-acute-static-stretch-on.html). They found stretches less than 45 s don't have a negative influence. I hope this helps.

A well written article, but I would hesitate to call for the removal of SS from routines. There is a place and time for SS, and I would challenge anyone to show me athletes that in some form and function don't utilize this form of stretching. This has been a hot topic for a while, and I truly appreciate the dialogue, but remember, there are no absolutes for everyone. Our athletes utilize a variety of both dynamic and static stretches in their pre and post routines, and have found that the SS's are useful after they perform the dynamic stretches. Their choice not ours, and discouraging them from utilizing what makes them feel adequately warmed up, or cooled down is not my position. There is not enough true and absolution for me to ban or discourage SS use. Question: has anyone suggested to the physical therapist or physician that the static stretching utilized in their daily practice is contraindicated?

Ken, thanks for weighing in. By no means are we saying that static stretch should be abandoned, altogether. The data from this and other articles is indicating that perhaps there needs to be a restructuring of the warm-ups and cool-downs. Static stretching does have a time and place, but studies are showing that pre-activity warm-up may not be the right time and place. With teams looking for any sort of competitive advantage, it would make sense to eliminate a facet of warm-up that statistically indicates a negative impact on performance. As an ATC myself, why would I wittingly put my team at a disadvantage from a performance standpoint, before the match even gets going? Let the other team static stretch and incur performance deficits, but not mine! To your other point about the athletes deciding what they do as their routine, in my experience, when it comes to health, performance and on-field items the athletes engage in that comes from the coordinated efforts of the head coach, ATC and strength coach. As the paid professional, armed with this info, I'd make sure that I got it in front of those other individuals in order to have the best possible competitive edge. No matter what is in place, sooner or later its going to become routine. I'd much rather the routine be set by people who are skilled and trained to institute these types of changes.

Also, Bear in mind that this study is a meta-anlaysis. They crunched the numbers of 104 studies and they were able to find statistic differences in 2 of the 3 categories they were investigating. That might not qualify as absolution, but it sure is a lot of studies.

Static stretching is used to correct, this does not mean that it cannot be utilized before activity/competition. If the individual needs to correct some imbalances prior to activity then by all means use static but follow up with active and dynamic movements to turn those muscles back on and the individual will be fine. Its when you perform static stretching to correct and do not follow up with active/dynamic movements that will lead to a decrease in performance......Is static stretching bad, no, just use it properly. I feel this is where the research has been confusing to many, continue to use it if warranted but remember to reactivate those muscles so you dont experience the negative effects...

Hi Yusuf: Thanks for the comment. Forget if static stretching is bad or good. I think its important that we need to ask is why do we perform static stretching? Once you answer that then the questions arise: Is there evidence to support doing static stretches before exercise to achieve this goal?Does static stretching achieve this goal better than dynamic/active stretching?Is doing the static stretches before exercise the best time to achieve this goal?

Also, do we have sufficient evidence that you can "reactivate those muscles" after static stretching?

Thanks Mark, don't misunderstand my position...I agree with you that dynamic stretching is a better way. That has been proven beyond question; my issue here is that the studies may prove there to be an impact on strength, but for how long and to what extent? I get concerned about studies that are ongoing without complete answers. Let me preface this by saying my comments are not intended to sound brash, but it is a worry that I have heard voiced in many circles: Are these studies performed to the standards that I would expect my child to adhere to, is the target audience correct, and if the studies prove little to no true conclusion, then what? If the researchers are going to publish this material, lets do it in a way that the information goes to the right people. Honestly I hope coaches read this information and make some changes, but I also look at the articles that come in specific sport magazines and wonder who let this quackery out into the public discourse. Fundamental changes like this need to be purposeful and well thought out, not just "proven". I am all for positive and correct change, just not one out of knee jerk reaction and unsupported fact. I want this change, it just needs to be brought into the discussion with the evidence that gives me the ability to show coaches and athletes alike the positive impact it can have, not just I read a study that says....... We owe our athletes every advantage they can muster without cheating, but we also owe it to them to be correct in our advice and provide sound and reliable information.

Ken, some studies have shown negative impacts incurred by static stretching can last upwards of 30 minutes post-stretch. In an effort to address some of your concerns: 1. I think that the standards to which they are adhered to has to be a global effort, from all facets of structured sports and performance. No child is doing any form of stretching prior to going out into the neighborhood and playing ball, so from an unsupervised standpoint I think its a moot point. 2. As far as the target audience goes, I would say, yes, the information by and large is being published in journals that are most appropriate. If I'm not mistaken, my other write-up about dynamic stretching vs static stretching came from the Journal of Strength and conditioning. The key is the appropriate people making the effort to go and find it, that's why an effort like this blog is so valuable. We are constantly putting the most up-to-date research in a concise format to make it relevant to sport, sport medicine and performance. You know as well as I do, some people work harder at their trade than others. AS far as just publishing to just publish, there might be some people out there that do that, but the sheer effort to get something to actually go to print is a long-haul. Jeff and Steve here at SMR can attest to that better than I can, but these researchers' names and careers are riding on these studies, and I'd venture to say that most aren't treating it like a mill. They want solid credible evidence being put into circulation, not just volume.

I totally understand where you're coming from about some of the things that you see in magazines. What I read is like the company that I keep. Case in point. Men's Health actually does a VERY good job of citing research in their articles. They tell you what institution it comes from and from what journal. They give you the ability to find it for yourself. I read this magazine, but shy away from Men's Fitness, because it's more of a strength mag and has an associated meathead persona, that's not who I am, that's not who I hang with. It might sound ridiculous, but if there is somebody you wouldn't sit down with and have a beer, why would do the same with a resource like a journal or a magazine you know to be below your standards?

As to how to make the change, I'd encourage you to read my last comment on the post that is linked in this write-up. I think it's a good starting point on how to get the ball rolling.

Just a few random thoughts....Why does stretching always need to be compared to athletic performance??What are the aims of static vs dynamic stretches- same/different??

I'm a PT. I use static stretching primarily to elicit the creep response due to soft tissue exhibiting viscoelastic properties. I use long duration (20 min or more multiple times per day) to create a permanent deformation. Short duration stretching (30-60 sec) does nothing more than cycle a spring. No deformation. No change in muscle length. This is needed when there are long standing issues of muscle length and strength asymmetry.

Dynamic stretching seems to work on a different mechanism. If someone improperly uses their HS for instance- as a primary hip extensor as opposed to a knee flexor, or they never cease muscle activation and use it ecc/concentrically

Dynamic stretching is great to re/establish proper firing of select muscle groups, and to allow synergists to work properly. If for ex the HS has been chronically shortened, the quad may not be working properly. By using the quad to stretch the HS it may alter muscle spindle activity and alter the muscles resting lengths.

Other thoughts- muscles may be in a protective spasm due to a facilitated segment and may resist all attempts to change length. More hypertrophy equals more stiffness due to Titin. By careful examination muscle stiffness patterns emerge and can be dealt with through specific movements that simultaneously shorten and lengthen the appropriate musculature. It would be interesting to do a study comparing dynamic and static stretching vs neuromuscular re-Ed on performance testing.

As a former NCAA collegiate athlete, static stretching certainly has its place in warm-up and cool-down activities. I think it should always be performed in conjunction with light cardiovascular warm-up and also dynamic stretches. As clinicians, PT's are taught to Incorporate a multitude of disciplines and treatments in order to maximize outcomes... I think the same concept needs to be applied with static/dynamic stretching/cardio with respect to warm-up to maximize performance.

First, static stretching doesn't always have to be studied in relation to athletic performance but it raises the question about whether static stretching, as commonly used in the athletic setting, is appropriate. One could try and extrapolate those findings to the potential influence static stretching may have prior to strengthening/neuromuscular training in the rehab setting but more research would be helpful in assessing if that is appropriate.

The aims of the stretching is one of the key issues to address. If your goal is to improve range of motion then long-duration static stretching is effective. If the goal is to be a component of a warm-up protocol and reduce the risk of reinjury then there may be more issues. These studies don't question the potential benefit of static stretching on range of motion, they question the appropriateness of these stretches when used prior to exercise/athletic performance (you can still do them during your cool down; these studies don't advise against it).

It's important to appreciate that these studies are focusing on a specific application of an intervention and not dismissing the intervention. For example, shoulder strengthening might be an effective treatment for shoulder pain but if a study came out suggesting shoulder strengthening doesn't improve knee pain we wouldn't stop strengthening shoulders in patients with shoulder pain.

In the era of evidence based medicine, doing an intervention b/c it is what was always done is not appropriate. We need to judge the level of evidence available for interventions when applied in certain populations and under certain conditions with particular goals. These studies are highlighting that static stretching, a very value intervention under the right circumstances, deserves to be rethought when administered prior to certain exercises. It doesn't question the value of static stretching for patients status post total knee replacement or the value of static stretching as part of the cool down. These studies should cause us to sit back and ask why do we perform static stretching? Is there evidence to support this goal and does static stretching achieve this goal better than dynamic/active stretching?

"I'm a PT. I use static stretching primarily to elicit the creep response due to soft tissue exhibiting viscoelastic properties. I use long duration (20 min or more multiple times per day) to create a permanent deformation."

Isn't this being debunked by current research? There hasn't been any evidence that muscles actually increase their length. Current research points to a neurological mechanism which increases ones tolerance to stretch..

Jeff, well said. The whole point of SMR is to inform. From there, we can go on to validate what it is that we are doing clinically, or to challenge sacred cows like pre-activity static stretching.

Does static stretching have its place, yes. Is it before practices and games, probably not so much. It is more than likely more indicated ina clinical setting as opposed to a functional/sports performance setting.

At nopoint are we saying static stretch is to be abandoned. We are stating that structurally, we might have to rethink how we prepare a body before activity

Muscle lengthening is attained by adding sarcomeres in series as opposed to in parallel. There are no conclusive human studies at this point, but one only needs to examine the effects of immobilization and muscle length. To truly describe muscle changes we need to speak of shortness, stiffness, and excessive length. Tight does not convey the muscles ability to fully lengthen. Short does. We need to further examine which muscles we are actually stretching as well. Could be one or more synergists. I'm all for evidence based practice. It just seems difficult to extrapolate pertinent clinical information from clinical trials. Personally I do a thorough assessment of muscle length strength and stiffness and only stretch what's needed. More than stretching though is proper joint alignment and proper use of synergists and antagonists properly.

Read that article you referenced. A number of issues were presented. No real way to measure "end points" other than pain perception. Torque is difficult to quantify across testing. The duration and frequency of stretching was inconsistent- and 5x/wk for 20 minutes was described as excessive and not given due attention. As well patients were a symptomatic. Two joint muscles seemed easier to analyze vs one it muscles. Focus seemed to be placed on shifting the torque curve to the R to prove a change. Not a true outcome measure if you asked me. It was a good meta analysis of previous research but would take a long time to review the methods of cited research. There was no mention of age, fitness level, occupation, etc. I would be more convinced about the results if it were more narrow in scope. Ex- patients with LBP and the effect of static stretching of the hamstrings with pain and function both being assessed. I also think more specificity is needed to ensure the lumbar spine isn't flexing instead of pure hamstring excursion. The sensory explanation might fit well into the facilitated segment theory. And as always "more research is needed". Then there's the total end-range time theory.....

In regards to where research is published. Good research studies end up being cited in various "athletic magazines", and as Mark stated -one needs to read these carefully. Many "youth coaches" are parents without any type of sports medicine background, and many high school coaches also do not have a sports medicine background. They read an excerpt in a magazine saying "static stretches decrease athletic performance" and without further investigating, they change their warm-ups to dynamic stretching only (often times done incorrectly) and very few teams perform post practice or post game cool down static stretching. Also - the authors of the research studies extrapolate to "the young", but if children and adolescents are growing still, does static stretching help prevent more injuries? Injury prevention in the pre-high school and early high school years is more important than sports performance. Again, if anyone has any research done on the effects of static strengthening and injury prevention in growing children/adolescents, I would appreciate it!

Well, I would say that such studies are highlighting that static stretching, a very value intervention under the right circumstances that deserves to be rethought when administered prior to certain exercises but still that is not enough to come to a conclusion.

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